/*
 * @(#)MD5.java   0.3-3 06/05/2001
 *
 *  This file is part of the HTTPClient package
 *  Copyright (C) 1996-2001 Ronald Tschal�r
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public
 *  License as published by the Free Software Foundation; either
 *  version 2 of the License, or (at your option) any later version.
 *
 *  This library is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public
 *  License along with this library; if not, write to the Free
 *  Software Foundation, Inc., 59 Temple Place, Suite 330, Boston,
 *  MA 02111-1307, USA
 *
 *  For questions, suggestions, bug-reports, enhancement-requests etc.
 *  I may be contacted at:
 *
 *  ronald@innovation.ch
 *
 *  The HTTPClient's home page is located at:
 *
 *  http://www.innovation.ch/java/HTTPClient/ 
 *
 */

package org.everrest.http.client;

import java.io.UnsupportedEncodingException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

/**
 * Some utility methods for digesting info using MD5.
 *
 * @author Ronald Tschal�r
 * @version 0.3-3 06/05/2001
 * @since V0.3-3
 */
class MD5 {
    private static final char[] hex = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f',};

    /**
     * Turns array of bytes into string representing each byte as unsigned hex
     * number.
     *
     * @param hash
     *         array of bytes to convert to hex-string
     * @return generated hex string
     */
    public static final String toHex(byte hash[]) {
        StringBuffer buf = new StringBuffer(hash.length * 2);

        for (int idx = 0; idx < hash.length; idx++)
            buf.append(hex[(hash[idx] >> 4) & 0x0f]).append(hex[hash[idx] & 0x0f]);

        return buf.toString();
    }

    /**
     * Digest the input.
     *
     * @param input
     *         the data to be digested.
     * @return the md5-digested input
     */
    public static final byte[] digest(byte[] input) {
        try {
            MessageDigest md5 = MessageDigest.getInstance("MD5");
            return md5.digest(input);
        } catch (NoSuchAlgorithmException nsae) {
            throw new Error(nsae.toString());
        }
    }

    /**
     * Digest the input.
     *
     * @param input1
     *         the first part of the data to be digested.
     * @param input2
     *         the second part of the data to be digested.
     * @return the md5-digested input
     */
    public static final byte[] digest(byte[] input1, byte[] input2) {
        try {
            MessageDigest md5 = MessageDigest.getInstance("MD5");
            md5.update(input1);
            return md5.digest(input2);
        } catch (NoSuchAlgorithmException nsae) {
            throw new Error(nsae.toString());
        }
    }

    /**
     * Digest the input.
     *
     * @param input
     *         the data to be digested.
     * @return the md5-digested input as a hex string
     */
    public static final String hexDigest(byte[] input) {
        return toHex(digest(input));
    }

    /**
     * Digest the input.
     *
     * @param input1
     *         the first part of the data to be digested.
     * @param input2
     *         the second part of the data to be digested.
     * @return the md5-digested input as a hex string
     */
    public static final String hexDigest(byte[] input1, byte[] input2) {
        return toHex(digest(input1, input2));
    }

    /**
     * Digest the input.
     *
     * @param input
     *         the data to be digested.
     * @return the md5-digested input as a hex string
     */
    public static final byte[] digest(String input) {
        try {
            return digest(input.getBytes("8859_1"));
        } catch (UnsupportedEncodingException uee) {
            throw new Error(uee.toString());
        }
    }

    /**
     * Digest the input.
     *
     * @param input
     *         the data to be digested.
     * @return the md5-digested input as a hex string
     */
    public static final String hexDigest(String input) {
        try {
            return toHex(digest(input.getBytes("8859_1")));
        } catch (UnsupportedEncodingException uee) {
            throw new Error(uee.toString());
        }
    }
}
